1. Field of the Invention
The present invention relates to a cooperative autonomous distributed control method, in an environment having a constraint on a resource availability for a system to be controlled, such as distributing power or aggregating data traffic under the limited flow and flux rate constraint, adapted to allow a strategy for reliably satisfying the constraint and simultaneously achieving or maintaining respective predetermined performances specifications at each entity in a system, via an autonomous adaptation mechanism by each entity member, which has the highest need for the resource to be allotted to itself at any given instance and also takes turns to play the role, without providing a system a centralized management entity.
2. Description of the Related Art
First of all, key terms to be used in the specification and the appended claims will be summarized as follows:                “Resource”: a manipulated variable (i.e., control variable), such as electric power or data traffic (i.e., data flow rate), to be input into a system within a unit time;        “Power Amount”: an integrated index of the input power;        “Information Amount”: an integrated index of the input data traffic;        “Performance”: an index of state pursued such as temperature, buffer utilization ratio or the like;        “Entity”: a constituent element of the system, such as a subsystem or a component, which is distributedly allocated to each location;        “Management Entity”: any one of the entities which serves as a central server having authority to determine a strategy of the system, at any given instance;        “Network”: a channel or a mechanism which allows information to be exchanged between respective ones of the entire entities of the system;        “Bidding”: Sending out (i.e., transmitting) a tender request to the entire entities via the network, wherein information responding thereto will be reported from the entities;        “Reporting”: in response to the tender request, reporting back to the entity having the server's authority, by issuing, when the performance is below a lower limit index, an On Card describing along with a difference index between the lower limit index and a current performance index, or a Coast Card describing along with a difference index between a nominal turn-on interval index and an elapsed number of time-frames after the latest turn-on instance, or by issuing, when the performance is above an upper limit index, a Skip Card;        “Evaluating”: Based on the tendered information, selecting one of the entities which tenders information with a maximum evaluation index;        “Committing”: Executing a control operation;        “Shifting”: Delegating the authority of the management entity to another one of the entities;        “Agent”: a software provided in each of the entities and configured to allow the entity to make an autonomous determination;        “Time Frame”: a predetermined time width during which electric power is input, i.e., a time interval during which one cycle of the functions of bidding, evaluating, committing and shifting is performed; and        “Interval”: a numerical index which represents a time interval during which each of the entities performs the functions, by the time frame.        
Depending on adequacy of initiation/discontinuation of resource consumption associated with execution (i.e., commitment) of respective controls for a plurality of entities of a system, such as activating/deactivating of a train's power system, turn-on/turn-off of an air-conditioner in business offices and households, or turn-on/turn-off of heaters in various sections of a satellite, an amount of resource consumption is likely to go beyond a capacity of the resource supply capability to the entire system (distributing power or aggregating data traffic). This problematic phenomenon is often seen in many large-scale systems, where it results in deterioration in efficiency of effective resource utilization. Moreover, the phenomenon causes occurrence of major power outage, crash of communication functions due to access concentration, or deterioration in power utilization efficiency of a satellite system.
There has been known a technique of providing a specified management entity in a system and allowing a control strategy for satisfying a constraint on an aggregated resource by the determination at the specified management entity. There has also been known a technique of allowing a control strategy for achieving or maintaining a performance of the entire system to be cooperatively determined by each entity distributed in the system. However, no technique has existed which is designed to determine a control strategy for satisfying both the requirements, i.e., to allow a control strategy for satisfying a constraint on an aggregated resource and simultaneously achieving or maintaining a performance of the entire system to be cooperatively determined by each entity autonomously and distributedly.
The following Patent Publication 1 relates to an operational technique for a computer in an environment having a constraint on a memory resource. This technique is different from a dynamic/adaptive-type distributed control configured to satisfy a resource constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publications 2, 3 relate to a technique for efficiently performing file relocation in a computer within a short period of time. This technique is different from the dynamic/adaptive-type distributed control configured to satisfy a resource constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved,
The following Patent Publication 4 relates to a method of evaluating a performance of remote calling to be performed between computers. This method is different from a control method as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 5 relates to a technique for distributedly arranging and inserting a plurality of registers in a computer. This technique is different from the dynamic/adaptive-type distributed control configured to satisfy a resource constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 6 relates to a technique of supporting the uneven memory access for operating systems, in which virtual and physical memories are allocated by using plural memory pools and frame treasuries. This technique deals with use of the virtual resource and is different from the dynamic/adaptive-type distributed control configured to satisfy a resource availability constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 7 relates to a system designed so that the resources that the deleted function uses are released and used by other functions through a monitoring processor. In contrast, a control scheme of the present invention has no need for providing such a specified monitoring management entity. Further, instead of the approach of creating a free resource, the scheme of the present invention is configured such that a plurality of entities take turns cooperatively to perform a processing of dynamically allocating a resource to respective entities consuming the resource. Thus, the system disclosed in the Patent Publication 7 is totally different from the scheme of the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 8 relates to a search control for an information service computer. This control is different from a control configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 9 relates to a management system for a discard priority processing in a computer. This system is different from the dynamic/adaptive-type control scheme as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 10 relates to a technique for allocating a resource. This technique is different from the scheme configured to solve a problem in control under a given resource constraint based on a distributed processing, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 11 relates to a technique for dividing a resource into two or more. This technique is different from the scheme configured to dynamically allocate a resource to each entity consuming the resource without division of a resource, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publication 12 relates to a technique for ASIC (application specific integrated circuits) design. This technique is different from a control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention, and the problem in the “Background of the Invention” remains unsolved.
The following Patent Publications 13, 14 relate to a technique for simultaneously performing a resource reallocation processing in all entities. This system assumes every information in the system are shared among all entities (agents) and is different from the scheme of the present invention in which the number of entities determining and executing a strategy is limited to one at any given time without a specified management entity. Moreover, the technique disclosed in the Patent Publications 13, 14 includes the step of evaluating respective improvement amounts in the entire entities. Differently from this technique, the method of the present invention has no need for such an evaluation. The present invention does not request processing at the entities other than an instantaneous server entity, and the system is free from computational and communication burdens.
The following Patent Publication 15 relates to a technique for defining planning and resource allocation separately. This technique is different from the control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention.
The following Patent Publication 16 relates to a technique specialized in data compression. This technique is different from the control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention.
The following Patent Publication 17 relates to a technique for solving conflicts by means of an exception handler. This technique is different from the control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention.
The following Patent Publications 18, 19 relate to a technique for performing a resource management based on a graph. This technique is different from the control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention.
A technique disclosed in the following Patent Publication 20 is different from the scheme of the present invention designed to dynamically allocate a bidding agent without a specified management entity.
The following Patent Publications 22, 23, 24 relate to a technique based on a specified management entity. This technique is different from the control scheme configured to dynamically allocate a resource to each entity consuming the resource under resource constraint, as set forth in the present invention.                [Patent Publication 1] JP 2005-006145A        [Patent Publication 2] JP 2003-296149A        [Patent Publication 3] JP 2003-296148A        [Patent Publication 4] JP 2003-186707A        [Patent Publication 5] JP 11-272641A        [Patent Publication 6] JP 09-237215A        [Patent Publication 7] JP 09-231148A        [Patent Publication 8] JP 09-204436A        [Patent Publication 9] JP 09-116540A        [Patent Publication 10] JP 06-028378A        [Patent Publication 11] JP 05-250298A        [Patent Publication 12] JP 11-502646A        [Patent Publication 13] JP 09-297689A        [Patent Publication 14] JP 07-006157A        [Patent Publication 15] JP 07-006142A        [Patent Publication 16] JP 2003-519945A        [Patent Publication 17] JP 2001-511555A        [Patent Publication 18] U.S. Pat. No. 6,859,927        [Patent Publication 19] U.S. Pat. No. 6,842,899        [Patent Publication 20] U.S. Pat. No. 6,801,819        [Patent Publication 21] U.S. Pat. No. 6,732,019        [Patent Publication 22] U.S. Pat. No. 6,459,683        [Patent Publication 23] U.S. Pat. No. 5,742,772        [Patent Publication 24] U.S. Pat. No. 6,243,396        
As mentioned above, depending on adequacy of initiation/discontinuation of resource consumption in respective entities of a system as shown in FIG. 1, such as activating/deactivating of a train's power system or turn-on/turn-off of an air-conditioner, a problem that an amount of resource consumption goes beyond a capacity of resource supply to the entire system is often seen in many large-scale systems. Although a power supply capacity required for each entity is averagely an extremely low index, it has to be set to avoid an undesirable situation where a peak of resource consumption appears due to simultaneous initiation of resource consumptions in the entities as shown in FIG. 2.
Unfortunately, with a certain probability, these systems take an operational risk due to excessive resource consumption. This problematic phenomenon is also observed during concentration of data traffic in a data acquisition bus or momentary concentration of access in mobile communication. A solution for these problems is how to dynamically allocate a resource to each entity consuming the resource shared in terms of time, and simultaneously achieve or maintain a target performance of the entire system, under constraint on an available resource.
Specifically, as shown in FIG. 3, a specified management entity may be provided in a certain facility or apparatus to perform an operation of collecting data about a need for resource supply/consumption in a system, and flattening the collected data rate in a time-division manner, so as to solve the above problem as shown in FIG. 4. In fact, a dedicated processing unit (manager) adapted to carry out the above function in a certain cycle is used for thermal control in an actual satellite, so as to re-allocate a resource to achieve an effect of flattening a power supply/consumption rate while suppressing a peak of the power supply/consumption.
This technique can be applied only to a system having a predetermined configuration. That is, if a new component (entity) is added, or an existing component (entity) is removed, or if a plurality of existing components are rearranged, the control system has to be fundamentally reconfigured. Actually, a satellite system, such as a thermal control system, will be obliged to be reconfigured every time a new satellite is designed. Moreover, the scheme using a specified management entity involves a risk that a failure of the specified management entity directly leads to a failure of the entire system, and has the problem about excessive increase in instrumentation such as harness and cables for implementation. In addition, the system verification requires tremendous time and budgets.
In view of achieving the above function in any type of system in a general-purpose manner, it is essential to establish a scheme capable of determining a strategy without providing a specified management entity. This scheme means a control configured to satisfy a constraint on a resource availability while maintaining an operating state and allowing separation/integration or collection/distribution of the resource.
As above, there is the need for a control scheme capable of determining a strategy for satisfying a constraint on a predetermined aggregated resource and simultaneously achieving or maintaining a performance of each entity, without providing a specified management entity, and robust against changes in system configuration.